cross-posted from: https://feddit.org/post/19852594
Edit: Be aware that some people try to post misinformation here, such as that such plants are not safe in the case of a power failure (untrue), or that they are not economical (untrue, their advantage is that they have very low installation costs).
There are currently talks about tightening these regulations, to the point where it is no longer feasible to use these kind of systems :(